A connection-less protocol such as a non-volatile memory express (NVMe) for flash storage is becoming widespread as a protocol used by a storage device of a storage system. Further, a method of adding a storage device by cascade-connecting a backend switch is mentioned as a means used for easily expanding the capacity of a storage system.
PTL 1 is known as, for example, a technique that evenly uses the performance of each storage device when a backend switch is cascade-connected. PTL 1 is a technology that evenly uses the performance of each storage device such as a serial attached SCSI (SAS) which is a connection storage protocol.